Oh boy. The name already suggests something Mary Sue as hell, so hopefully my first impression is proven wrong.

Subject SCP-# is to be kept in a subterranean complex hollowed from bedrock. The chamber may not be located within ten kilometers of any urban center to prevent SCP-#2's access to victims. The main containment chamber must be 16 meters long and wide, and at least three meters tall.

This is an insane amount of space to contain a tiny piece of rock and a book.

SCP-# is a small piece of quartz, of composition usually found in [DATA REDACTED]

This is a pretty lazy use of a redaction. If its composition is "usually" found somewhere, why would that be something so classified as to warrant deletion?

Should SCP-# be able to absorb enough blood, namely 245 liters, and the proper incantation spoken, an instance of SCP-#2 will appear, a being of extreme speed, strength and total invulnerability due to anomalous displacement in the physical realm.

First of all, 245 liters is like 45 adult human beings. I'm not sure if that's the number you were going for.
Second of all, this is a super-overpowered Mary Sue-style thing that's neither scary nor interesting enough for me to be engaged in this as a reader.

Within the steel box SCP-# rests on is a book, denoted as SCP-#1. It appears to be a grimoire made of papyrus harvested from the Central Egyptian region roughly thirty-five hundred years ago, written in ancient Babylonian and translated into Egyptian on the corresponding page.

Why is this completely unrelated item part of the same SCP? I feel like either the crystal or the book needs to be removed from this equation; it just feels cluttered.

Breaking the door open, the team observed a white crystal, described as having a sickly glow about it. Each man almost immediately began to convulse and bleed heavily from every orifice in their body.

Here's one of the most valuable lessons I ever learned as a horror writer: death is not scary. A Thing What Kills You, with no additional hook or point of interest beyond "it kills you", is not scary. It's just corny at this point.

It is gathered from translations that SCP-# would be sealed in this chambers until the Pharaoh called for its usage in battle, a frequent happening in Amenhotep’s time.

I could go on, but to be blunt, this just isn't interesting. If you're set on keeping the same concept, you're going to have to do some serious work to de-Mary Sue-ify this thing and add something that makes the reader interested.

Thank you for your feedback. I put a lot of thought into this article, but obviously it was in the wrong direction. I have a few ideas for how I might take your suggestions, but honestly I am just scrap this and try out a different idea. Pretty much however I swing this from here is going to be a bit too "Marry Sue" as you put it. Thanks for alerting me to it and giving me suggestions though!

Major edits have taken place since last I posted this. I've re-written the whole summoning concept and made the entity far less Mary Sue. I have some problems with my ineptness in the article. Can't seem to get line spacing or tabbing to work. Anyways, any criticism, coding helps, and general feedback is greatly appreciated.

Sorry to repost on my own SCP. I've done some editing and would appreciate feedback. Specifically, my original document was called too Mary Sue. I've tried to fix that. Also I've been told the sacrifices could be rework. Any suggestion is helpful

For what it is, it really isn't that bad. Though it feels more like the plot to the next Mummy movie than an SCP. As far as the SCP database goes, it's different. However it's something we have all heard before. I would suggest finding a stronger base. If youre dead set on using this idea however, I would suggest focusing on SCP-#-2. The humaniod cobra.